400 amp service -- what is required?

Question for the electrical experts:

I am building a new home that requires more than a 200 amp service panel. I specified a 400 amp panel. The question is what is required for a 400 amp panel? My vision was that a 400 amp panel was just a 400 amp meter box connected to a 400 amp panel (like Square D QO series flush mount). Simple enough in my mind.

Well what seemed Simple Enough the electrician has made seem more complicated. He mentioned that yes there will be the 400 amp panel and a 400 amp meter box but then he mentioned some other large box on the outside of the house. Something about that box having two large switches.... What is that??? Sounds odd and unneeded to me.

Re: 400 amp service -- what is required?

Originally Posted by roamerr

Well what seemed Simple Enough the electrician has made seem more complicated. He mentioned that yes there will be the 400 amp panel and a 400 amp meter box but then he mentioned some other large box on the outside of the house. Something about that box having two large switches.... What is that??? Sounds odd and unneeded to me.

As I understand it, you are required to have a breaker to disconnect the power between the meter and the breaker box if the run from the meter to the breaker box is more than 15 feet.

Disclaimer: This is just what I picked up from a quick Google search for "400 amp service disconnect" and while I know my way around a breaker box (I used to work for an electrician), this information is only my opinion and should not be treated as fact until proven to be such.

Aaron Z

A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
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Re: 400 amp service -- what is required?

It is also possible that box will have a transformer. Huge currents require huge conductors, which cost a lot of money. Operating at a higher volatge allows the use of smaller conductors (= less money), switching over to the large conductors once the voltage is stepped down by the transformer. The cost of the transformer needs to be weighed against the cost of the conductors.

Alcohol, Tobacco and Firearms should be a convenience store, not a government agency.

Re: 400 amp service -- what is required?

Re: 400 amp service -- what is required?

When talking to Entergy, my local electric company, about installing service where I plan to build a house they said that most 400 amp services are actually 320 amps with 2 200 amp panels and that it would be more expensive for them and me to install true 400 amp service.

You might google "true 400 amp" or "400 amp versus 320 amp" to find lots of info on this topic.

Re: 400 amp service -- what is required?

I have two 200 amp panels for my house. It goes from the pole, to the meter, to a 1,200 amp breaker cabiner with 6 200 amp breakers. From there, I ran two lines for each 200 amp panel in my home. This is a commercial setup, and while the meter box was included, the breaker cabinet was on me, and very pricey.

Re: 400 amp service -- what is required?

I have a 400A service in my house...Just a 400A meter on the outside wall feeding 2 200A 42 space panel's in the house. No disconnects between the meter base and the panel's-just the standard main breaker in the 200A panel's.

The main reason for the 400A service is breaker capacity because you run out of circuits quickly with all the dedicated circuits required today.